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N.K. Tovey (杜伟贤 ) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук

Recipient of James Watt Gold Medal

1

Control of Energy use in Buildings Building Regulations

CLIMATE CHANGE GOVERNANCE AND COMPLIANCE

NBS-M017/NBSLM04D 2013

Session2 Session3

Building Regulations

• Review of Building Regulations in UK– Factors affecting energy consumption and carbon emissions

– Standard Assessment Procedure

• Code for Sustainable Homes

• Energy Performance Certificates

• Introduction in Indian Building Regulations

• Introduction to Chinese Building Regulations

2

3

• Until 1965 there were no national Building Codes.• Previously Local Bye Laws prevailed and modes of construction varied

from one part of UK to another. • First Building Regulations did not include requirements for Energy

Conservation – these came in 1976 • Building Regulations are divided into sections and associated Approved

Documents (ADs)• Part A: Structural Maters• Part B: Fire• Part F: Ventilation• Part H: Heat producing appliances• Part L: Energy Conservation and more recently carbon emissions

• Each Part has associated Ads e.g. for Part L the Approved Documents were originally ADL.

• Subsequently (from 2002) divided into ADL1 and ADL2 covering dwellings and non-dwelling separately

• Then after 2005 subdivided further into ADL1a and ADL1b covering new and existing buildings.

Introduction of Building Regulations

4

• First introduced as Part L in 1976• Basic Statement – largely following what was then common

practicee.g. cavity walls brick cavity block with no insulation: - no insulation in floor, minimal insulation in loft.

• 1994: First attempt to address overall annual energy consumption, although elemental method of compliance was still permitted

• 2002: Carbon Index introduced – but was flawed• 2006: Target Emission Rate and Dwelling Emission Rate

introduced.• 2010: Came into force Oct 1st 2010 – relatively minor updates

on 2006 Regulations but noticeable reductions in allowable emissions.

Changes in the Heating Standards of Houses

4

U-Value Specification with different Regulations

5

1976 1985 1990 1994 2000 2005 2010

U – Values W m-2 oC-1

SAP < 60

SAP > 60

External Wall 1.0 0.6 0.45 0.45 0.35 0.45 0.35 0.35

Roof 0.6 0.35 0.25 0.2 0.16 0.25 0.16 0.16

Floor 1.0 0.6 0.45 0.35 0.25 0.45 0.25 0.25

Windows Not specified 3.0 2.0* 3.3 2.0 2.0

Windows as % of external walls

17% 12% -

Windows as % of total floor areas

- - 15% 22.5% 25% 22.5% 25% 25%

Comparison of energy consumption for a standard detached house at various ages and improvements (Heat losses in W0C-1)

0

100

200

300

400

500

600

700

800

pre-war

post-war

1960s 1976 1985 1990 1994 2000

unimproved

25mm

50mm

100mm

100+CAV

100+DG

100+DG+CAV

150+DG

200+DG+CAV

250+DG+CAV

DG – double glazingCAV – cavity wall insulationNumerical value indicates thickness of loft insulation 6

Effects of built form on energy consumption (Heat loss WoC-1)

0

100

200

300

400

500

600d

eta

ched

sem

i-d

eta

ched

terr

ace

d

det

ach

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sem

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eta

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tto

m e

nd

top

en

d

mid

-sto

rey

en

d

bo

tto

m c

entr

e

top

cen

tre

mid

-sto

rey

cen

tre

2002

1976Houses Bungalows

Flats

7

Compliance to Building Regulations

• Compliance to Building Regulations may be achieved by one of several alternative methods.

– Elemental Method

• Specifies maximum U-value and perhaps maximum glazed area – valid until 2002 Regs

- still used in several other countries

– Target U-value – weighted average U-value allowed some flexibility in design

– SAP Rating (1994 Regs) – economic assessment

– Carbon Index (2002 Regs)

– Target Emission Rate (Current Regs)

8

Building Regulation: Compliance Summary

Up to and including 2000 Regulations • Elemental Method – specifying U-values of all fabric elements –

e.g. Windows, floors, walls, roofs• Target U-Value – allowed some flexibility of design.• SAP Rating – an economic measure – only permitted for

compliance in 1994 Regs.

2000/2002 Regulations• Carbon Index Method- a distorted Carbon Measure

2005/6 Regulations• Dwelling Emission Rating must be better than Target Emission

Rating. Latter is a derivative of the Target U-Value Method.

2009/10 Regulations• Retains DER and TER but expects a 25% improvement on

performance over 2005/6 standards

9

• Calculate Target U-Value – a function of areas of floor, roof, walls, windows etc– i.e. Weighted average U-Value over all fabric components

• Modify target – gas & oil boilers: actual SEDBUK efficiency

standard SEDBUK efficiency – electric & coal heating: divide by 1.15– No modification for heat pumps, biomass, biogas, CHP– Purpose of modifications is to give more freedom for designs using efficient oil or gas boilers

• Modify target if area south facing windows > area north facing windows

• Calculate ACTUAL weighted average U-value of all external surfaces

• Weighted average U-value must be <= Target value

10

Building Regulation: Compliance Target U – Value Method

SEDBUK Database

Standard Assessment Procedure

• Calculate U-values • Check U-values are achieved

– i.e. Check for bridging

• Calculate – gross heat requirements (Heat Loss Rate)– hot water requirements– incidental & solar gains– effective gains– effective internal temperature– corrected degree-day parameter– net space heating total energy requirement

• Select heating method (pumps, appliance efficiency)• Calculate Total Energy Requirement• Estimate energy costs of total space heating, hot water & pumps• Deflate energy by Energy Cost Factor (ECF)– e.g. 1994:0.96, 2001:1.05 etc• Estimate SAP on scale 0 – 100+ based on ECF It is the Economic Aspects which cause problems with SAP Rating

11

Critique of the Standard Assessment Procedure (SAP) • Energy efficiency index – but gives a rating that is monetary based not energy

based

• Assumes a general heating level in house – two zones (one living area one other). Does not allow for actual temperature settings.

• Hot water requirements based on floor area formula not occupancy

• Incidental gains based on floor area not occupancy

• Problem: Is this a sensible approach?

– If occupancy changes then Rating would change, but it is difficult to compare actual readings with predicted.

• Alcantar (2008) found problems with methodology for incidental gains etc

• 2010 Regulations partly address issue with regard to occupancy – e.g.• if TFA > 13.9: N = 1 + 1.76 × [1-exp (-0.000349 × (TFA-13.9)² )] + 0.0013 × (TFA-13.9) if TFA ≤ 13.9: N = 1

• N is the assumed number of occupants, TFA is the total floor area of dwelling.

12

2006 Regulations Dwelling Emission Rate is method of compliance- essentially the 2010 Regs are similar with only minor variations in detail

• Criterion 1

• A Dwelling Emission Rating (DER) must be calculated taking due account of the U-values, the size, the types of heating etc using the Standard Assessment Procedure (SAP)

• The DER must be shown to be less than the Target Emission Rating (TER) which is computed with the same size of building and U-values meeting those as specified in the Regulations.

Essentially this is a derivative of the target U – value method

• Details are shown in Section 2.1.11 of handout13

Criterion 2 – limits on design flexibility• Performance of the building must not be worse than a

given standard. • gives considerable latitude in design – the old trade-off

problem.

• However criterion attempts to limit this type of trade-off – see pages 5 and 6 of the Approved Document

Criterion 3 – Limiting effects of solar overheating• Requires that the effects of overheating in summer must be

addressed

14

2006 Regulations Dwelling Emission Rate is method of compliance- essentially the 2010 Regs are similar with only minor variations in detail

Criterion 4 Quality of Construction• Criterion requires evidence of actual performance – e.g.

changes arising from design modifications, quality of workmanship.

Some of the requirements involve pressure testing the building to ensure they have achieved those used in the design specification.

Criterion 5. Providing Information• Requires information on the maintenance and operation of

the building to be made available.

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2006 Regulations Dwelling Emission Rate is method of compliance- essentially the 2010 Regs are similar with only minor variations in detail

16

Simplified Description of Standard Assessment Procedure (SAP)Stage 1 Assess overall heating requirements for building (E)

Component U-Value Area Heat Loss Rate (W oC-1)

Walls Uwalls Awalls Uwalls * Awalls

Windows Uwindows Awindows Uwindows * Awindows

Floor Ufloor Afloor Ufloor * Afloor

Roof Uroof Aroof Uroof * Aroof

Air change Volume

Ventilation ach V V * ach * 0.361

Total Heat Loss Rate H = Σux*Ax + V* ach * 0.361

Annual Energy Requirement

E = H * DegreeDays *86400

Stage 2 Assess hot water/lighting requirements and incidental gains, efficiency of heating appliance and solar energy etc. Correct annual consumption to allow for these facts.

Analysis of Stage 1 and 2 generally sound – gives estimates to around 10-15%

Stage 3. Determine the Energy Costs to determine the SAP Rating– - Serious issues arise with stage

CALCULATION of SAP RATING

• While the Standard Assessment Procedure makes sense the final Rating known as the SAP Rating creates problems

• The SAP rating is related to the total energy cost by the equations:

• Energy Cost Factor (ECF)

= deflator × total energy cost / (TFA + 45) (10)

• The total energy running cost includes not only heating but also requirements for hot water, lighting etc as well as pumps/fans associated with heating. These are proscribed costs according to a table which are not actual costs.

• The deflator is a factor which varies according to energy costs and is intended to keep SAP Ratings constant with time irrespective of changes in fuel prices - this has not been the case in the past. But this still causes problems with relative changes between different fuels

17

Critique of the Standard Assessment Procedure (SAP) • Standing charge ignored for electricity, included for gas. Oil doesn’t have

a fixed charge

• Can lead to some perverse consequences– Lower efficiency oil heating can give a higher SAP rating than more efficient

gas

• Energy Cost Deflator is needed – Unnecessary complication that allows for inflation– But does not allow for differential prices changes between fuels

• SAP 1995 – possible SAP rating of over 110– SAP of 100 readily achievable

• SAP 2001 – widened scale (over 120) for consistency with existing scale

• SAP 2005 changed scale to have 100 for zero energy house – means all previous calculation have to be redone.

– Now possible to get > 100 if a house is carbon negative – i.e. will be exporting more energy than it consumes.

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SAP Rating 20092005SAP

Mains gas

LPG Oil Electricity Solid mineral

Biomass

1 1 10 1 6 12 910 9 20 9 16 21 1820 19 31 19 26 31 2830 29 41 29 37 41 3740 39 50 39 46 50 4750 48 59 50 56 59 5660 58 68 60 65 68 6570 67 76 70 74 77 7480 76 84 80 82 85 8390 85 92 90 91 93 92

100 94 99 100 99 100 100

Impact of Changing Methodology on SAP Rating

These changes are relatively small compared with changes in previous methodology changes – i.e. 1995 – 2001 and 2001 – 2006.However these demonstrate the problem of using Economic Cost as a Key Factor in determining the SAP Rating 19

Climatic Issue with 2010 Calculations

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Calculations have to take account of Climate Variations of Solar Gain for

Assessment of Cooling Requirements

But NOT Heating (even though heating requirements will vary by up to +/-25% from one part of country to another

Benefit of Solar Panels does not account for geographic variations in solar radiation even though this information is available for cooling calculations.

Calculating the TER• TER2010 = (Ch x FF x EFAh + Cl xEFAl) x (1–0.2)* (1 – 0.25)

i.e. a 25% improvement on 2005 This is partly to bring things in align with Code for Sustainable Homes

* The (1 – 0.2) represents a carry over from TER-2005 which indicated a 20% improvement on 2002 Regulations

• Where

Ch are the carbon emissions associated with for space heating and hot water including any used in circulating pumps,

Cl is the equivalent associated with lighting

FF is a fuel factor – this is NOT the Emission Factor for the Fuel

EFA is the relevant Emission Factor Adjustment and is a ratio of the emission factors used in the 2009 calculations divided by the equivalent ones in the 2005 calculations.

Improvements for 2010 - Environmental Impact Rating (EI)

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Improvements for 2010 - Environmental Impact Rating (EI)

• Carbon Factor (CF) = (CO2 emissions) / (TFA + 45) where TFA is the Total Floor Area• if CF >= 28.3 EI rating = 200 – 95 x log10(CF)• if CF < 28.3 EI rating = 100 – 1.34 x CF where the CO2 emissions are calculated according to the

Standard Assessment Procedure

• The EI rating is essentially independent of floor area

• It will vary slightly depending on actual plan shape

• A house with zero emissions will have the EI at 100

• An EI > 100 if a house is a net exporter of energy.

• Primary energy requirements are also calculated in a similar way to CO2 emissions.

22

• Letter Rating bands are assigned as followsIt applies to both the SAP rating and the Environmental

Impact rating (why the SAP Rating??). Rating Band

Improvements for 2010 - Environmental Impact Rating (EI)

EI Range Letter Rating

> 92 A

81 to 91 B

69 to 80 C

55 to 68 D

39 to 54 E

21 to 38 F

1 to 20 G

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24

How has the performance of a typical house changed over the years?

Bungalow in South West Norwich built in mid 1950s

Original Construction

• Brick – brick cavity walls• Metal windows•Solid floor no insulation•No loft insulation

25

Annual Energy Consumption

0

5000

10000

15000

20000

25000

30000

Interwar

post-war

1960s 1976 1985 1990 1994 2002 2006

kWh

House constructed in mid 1950s

Part L first introduced

~>50% reduction

First attempt to address overall consumption. SAP introduced.

Changing Energy Requirements of House

In all years dimensions of house remain same – just insulation standards change

As houses have long replacement times, legacy of former regulations will affect ability to reduce carbon emissions in future

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26

Annual Energy Consumption

0

5000

10000

15000

20000

25000

30000

Interwar

post-war

1960s 1976 1985 1990 1994 2002 2006 gas oil SAP2005

kWh

House constructed in mid 1950s

Existing house – current standard: gas boiler

Improvements to existing properties are limited because of in built structural issues – e.g. No floor insulation in example shown.

House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP 2005.

As Existing but with oil boiler

Changing Energy Requirements of House

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Annual CO2 Emissions

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

Interwar

post-war

1960s 1976 1985 1990 1994 2002 2006 gas oil SAP2005

CO

2 em

issi

ons

(kg)

House constructed in mid 1950s

Changing Carbon Dioxide Emissions

Existing house – current standard: gas boiler

As Existing but with oil boiler

Notice significant difference between using gas and oil boiler.

House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP 2005. 27

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Code for Sustainable Homes

Move towards Zero Carbon Homes

But what does Zero Carbon Mean?

N.K. Tovey (杜伟贤 ) M.A, PhD, CEng, MICE, CEnv

Н.К.Тови М.А., д-р технических наук

Energy Science Director CRed Project

HSBC Director of Low Carbon Innovation

Recipient of James Watt Gold Medal

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• Introduced over next few years to improve standards to ultimate “zero carbon house”

• But objectives of a low carbon future may be jeopardised if attention is not also paid to sustainable transport associated with new dwellings

The Future: Code for Sustainable Homes

0

2000

4000

6000

8000

10000

12000

14000

16000

1

Lighting

Refrigeration

Entertainment

Miscellaneous

Air/Public Travel

Washing/Drying

Private Car

HeatingData for 1 household with 2 cars

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The Code For Sustainable Homes

The Code for Sustainable Homes is a set of sustainable design principles covering performance in nine key

areas.

1. Energy and CO2

2. Water

3. Materials

4. Surface water run-off

5. Waste

6. Pollution

7. Heath and well being

8. Management

9. Ecology

9 key areas of performance….

http://www2.env.uea.ac.uk/cred/harrisongroup/Code_for_Sustainable_Homes.htm

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Code for Sustainable Homes: Certificates

Dwelling Emission Rate DER (Maximum 15 credits)% Improvement of DER over TER 2005

Credits Mandatory Levels

≥10% 1 Level 1

≥14% 2

≥18% 3 Level 2

≥22% 4

≥25% 5 Level 3

≥31% 6

≥37% 7

≥44% 8 Level 4

≥52% 9

≥60% 10

≥69% 11

≥79% 12

≥89% 13

≥100% 14 Level 5

True Zero Carbon 15 Level 6

Credits gained for different improvements

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0

1000

2000

3000

4000

5000

6000

7000

8000

Asconstructed

current SAPreference

Code 1 Code 2 Code 3 Code 4 Code 5 Code 6

CO

2 em

issi

on

s (k

g)

House constructed in mid 1950s

Implications of Code on Carbon Dioxide Emissions

Code 5: Zero Carbon House for Heating/Hot Water and LightingCode 6: Zero Carbon House overall but in reality is this achievable?

-10% -18% -25% -44%

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Improvements on the SAP 2005 standards as required by the different code levels can be met by:

• Improved Fabric performance• Lower U-values

• Technical Solutions• Solar Thermal• Solar Photo-voltaic• Heat Pumps• Biomass• Micro- CHP• Low Energy Lighting (SAP 2005 already specifies 30%)

Responding to the Challenge:

• Energy Service Companies may offer a solution for financing

• Issues of Carbon Trading

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What can be achieved through• Improved Fabric / standard appliance Performance• Using SAP 2005 standard reference• Explore different combinations of following improvements.

Item SAP reference

Improvement Option 1

Improvement Option 2

Windows U-value = 2 U-value = 1.4

Walls U-value = 0.35 U-value = 0.25 U-value = 0.1

Floor U-value = 0.25

Roof U-value = 0.16

Boiler efficiency

78% 83% default 90% SEDBUK

Responding to the Challenge: Technical Solutions

SEDBUK DataBase (Seasonal Efficiency of Domestic Boilers in UK)

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WEB PAGE: www.sedbuk.com/index.htm

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Annual CO2 Emissions

0

500

1000

1500

2000

2500

3000

A B C D E F G H

CO

2 em

issi

ons

(kg)

The Future: Code for Sustainable Homes

Option CO2 Emissions (kg) Reduction Credits

A SAP Reference 2504 0 0B Boiler η = 83% (default) 2377 5% 0C Boiler η = 90% (SEDBUK) 2229 11% 1D η = 90%: Walls: U = 0.25 2150 14% 2E η = 90%: Walls: U = 0.10 2034 19% 3F η = 90%: Windows: U = 1.4 2112 16% 2G C + D + F 2033 19% 3H C + E + F 1919 23% 4

Improvements in Insulation and boiler performance

Code 1

Code 2

Option H nearly makes code 3

SAP 2005 standardWalls: 0.35 Wm-2oC-1

Windows: 2.0 Wm-2oC-1 Boiler η 78%

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The Future: Code for Sustainable Buildings

All non-dwellings must display a certificate such as shown

• >10000m2 from 6th April 2008• > 2500m2 from 1st July 2008•All non-residential buildings > 1000m2 from 1st October 2008. •Separate assessments for air-conditioning plant will be phased in from 1st January 2009

Elizabeth Fry Building:

Initially Penalised because it does not have thermostatically controlled radiator values . Does not get credit for triple/ quadruple glazing – analysis system cannot cope!!!!!

There are no radiators!!!!!!

Indian Building Code• WEBSITE: http://www.hareda.gov.in/ECBC.pdf

• Also available at UEA at

– http://www2.env.uea.ac.uk/gmmc/energy/NBS-M14x/Indian_DRAFTECBC27MARCH2006.pdf

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Code was formulated following Energy Conservation Act of 2001

According to Saurabh Kumar, Secretary of Ministry of Power (18th April 2007), Code was to be trialled in demonstration areas from July 2007

An initial appraisal suggests that code tends to follow the equivalent of an Elemental Approach, but with differences

Unlike UK, elemental standards vary from region to region according to climate.

UK has 18 zones each with different Degree-Days, but elemental standards are same

[Technically Scotland could modify standards in Scotland]

Two identical houses in UK, one in South West, the other in North East Scotland, the energy consumption for space heating in latter would be 47% higher than former

40Is it sensible to have different standards in different climate regimes?

Indian Building Code

Climate Zone Hospitals, Hotels, Call Centers (24-Hour)

Other Building Types (Daytime)

Maximum U-factor (W/m2 oC-1)

Maximum U-factor (W/m2 oC-1)

Composite 0.352 0.352

Hot and Dry 0.369 0.352

Warm and Humid 0.352 0.352

Moderate 0.431 0.397

Cold 0.369 0.352 41

Example of U-values for walls

Based on Table 4.3.2 of ECBC 2006.Note: The U-value in the UK is 0.35 W/m2 oC-1

Indian Building Code

42

Chinese Building Code

China is adopting a similar approach to that suggested for India

Country/District U-Values (W m-2 oC -1)

Walls Windows Roof

Beijing (2003) 0.82 – 1.16 3.5 0.6 – 0.8

Beijing (current) 0.6

Shanghai (current) 1.0

Germany 0.5 1.5 0.22

Sweden 0.17 2.5 0.12

UK (2005 Regulations) 0.35 2.0 0.16

Canada 0.36 2.86 0.23 – 0.4

Hokk aido, Japan 0.42 2.33 0.23

Zones in USA similar to Beijing 0.32 – 0.45 2.04 0.19

Zones in Russia similar to Beijing

0.44 – 0.77 2.75 0.33 – 0.57

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Chinese Building Code